package utill;

/**
 * Provides a method to encode any string into a URL-safe form. Non-ASCII
 * characters are first encoded as sequences of two or three bytes, using the
 * UTF-8 algorithm, before being encoded as %HH escapes.
 * 
 * Created: 17 April 1997 Author: Bert Bos <bert@w3.org>
 * 
 * URLUTF8Encoder: http://www.w3.org/International/URLUTF8Encoder.java
 * 
 * Copyright 1997 World Wide Web Consortium, (Massachusetts Institute of
 * Technology, European Research Consortium for Informatics and Mathematics,
 * Keio University). All Rights Reserved. This work is distributed under the
 * W3C® Software License [1] in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.
 * 
 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
 */
public class URLUTF8Encoder
{

	final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05",
			"%06", "%07", "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e",
			"%0f", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17",
			"%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f", "%20",
			"%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29",
			"%2a", "%2b", "%2c", "%2d", "%2e", "%2f", "%30", "%31", "%32",
			"%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3a", "%3b",
			"%3c", "%3d", "%3e", "%3f", "%40", "%41", "%42", "%43", "%44",
			"%45", "%46", "%47", "%48", "%49", "%4a", "%4b", "%4c", "%4d",
			"%4e", "%4f", "%50", "%51", "%52", "%53", "%54", "%55", "%56",
			"%57", "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f",
			"%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68",
			"%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f", "%70", "%71",
			"%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7a",
			"%7b", "%7c", "%7d", "%7e", "%7f", "%80", "%81", "%82", "%83",
			"%84", "%85", "%86", "%87", "%88", "%89", "%8a", "%8b", "%8c",
			"%8d", "%8e", "%8f", "%90", "%91", "%92", "%93", "%94", "%95",
			"%96", "%97", "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e",
			"%9f", "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7",
			"%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af", "%b0",
			"%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7", "%b8", "%b9",
			"%ba", "%bb", "%bc", "%bd", "%be", "%bf", "%c0", "%c1", "%c2",
			"%c3", "%c4", "%c5", "%c6", "%c7", "%c8", "%c9", "%ca", "%cb",
			"%cc", "%cd", "%ce", "%cf", "%d0", "%d1", "%d2", "%d3", "%d4",
			"%d5", "%d6", "%d7", "%d8", "%d9", "%da", "%db", "%dc", "%dd",
			"%de", "%df", "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6",
			"%e7", "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef",
			"%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7", "%f8",
			"%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff" };

	/**
	 * Encode a string to the "x-www-form-urlencoded" form, enhanced with the
	 * UTF-8-in-URL proposal. This is what happens:
	 * 
	 * <ul>
	 * <li>
	 * <p>
	 * The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through
	 * '9' remain the same.
	 * 
	 * <li>
	 * <p>
	 * The unreserved characters - _ . ! ~ * ' ( ) remain the same.
	 * 
	 * <li>
	 * <p>
	 * The space character ' ' is converted into a plus sign '+'.
	 * 
	 * <li>
	 * <p>
	 * All other ASCII characters are converted into the 3-character string
	 * "%xy", where xy is the two-digit hexadecimal representation of the
	 * character code
	 * 
	 * <li>
	 * <p>
	 * All non-ASCII characters are encoded in two steps: first to a sequence of
	 * 2 or 3 bytes, using the UTF-8 algorithm; secondly each of these bytes is
	 * encoded as "%xx".
	 * </ul>
	 * 
	 * @param s
	 *            The string to be encoded
	 * @return The encoded string
	 */
	public static String encode(String s)
	{
		StringBuffer sbuf = new StringBuffer();
		int len = s.length();
		String hexLocal = "0123456789ABCDEF";

		for (int i = 0; i < len; i++)
		{
			int ch = s.charAt(i);
		
			if ('A' <= ch && ch <= 'Z')
			{
				sbuf.append((char) ch);
			} else if ('a' <= ch && ch <= 'z')
			{
				sbuf.append((char) ch);
			} else if ('0' <= ch && ch <= '9')
			{
				sbuf.append((char) ch);
			} else if (ch == ' ')
			{
				sbuf.append('+');
			} else if (ch == '-' || ch == '_' || ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')')
			{
				sbuf.append((char) ch);
			} else if (ch <= 0x007f)
			{
				sbuf.append(hex[ch]);
			} else
			{
				sbuf.append("%" + hexLocal.charAt((ch & 0xFF) >> 4));
				sbuf.append(hexLocal.charAt(ch & 0x0F));
			}
		}
		
		return sbuf.toString();
	}
	
	public static String encode(byte[] s)
	{
		StringBuffer sbuf = new StringBuffer();
		int len = s.length;
		String hexLocal = "0123456789ABCDEF";

		for (int i = 0; i < len; i++)
		{
			int ch = s[i];
			
			if (ch < 0)
				ch = 256 - ch;
		
			if ('A' <= ch && ch <= 'Z')
			{
				sbuf.append((char) ch);
			} else if ('a' <= ch && ch <= 'z')
			{
				sbuf.append((char) ch);
			} else if ('0' <= ch && ch <= '9')
			{
				sbuf.append((char) ch);
			} else if (ch == ' ')
			{
				sbuf.append('+');
			} else if (ch == '-' || ch == '_' || ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')')
			{
				sbuf.append((char) ch);
			} else if (ch <= 0x007f)
			{
				sbuf.append(hex[ch]);
			} else
			{
				sbuf.append("%" + hexLocal.charAt((ch & 0xFF) >> 4));
				sbuf.append(hexLocal.charAt(ch & 0x0F));
			}
		}
		
		return sbuf.toString();
	}

	public static String encodeHTML(String s)
	{
	    StringBuffer out = new StringBuffer();
	    
	    for(int i = 0; i < s.length(); i++)
	    {
	        char c = s.charAt(i);
	        
	        if(c > 127 || c=='"' || c=='<' || c=='>')
	        	out.append("&#"+(int)c+";");
	        else
	        	out.append(c);
	    }

	    return out.toString();
	}
}